Function Codes - Lenze i55AE125B Manual

9.8.6

Function codes

The mode of access to inverter data (parameters) is controlled via function codes.
Frame structure
Modbus Application Header (MBAP)
Transaction Protocol charac-
number ters
(always 0x0000)
2 bytes
2 bytes
Tab. 1: ADU (Application Data Unit)
Communication is established on the basis of the master/slave mode. Communication is
always started by a master request.
The inverter (slave) then either gives a valid response or outputs an error code (provided that
the request has been received and evaluated as valid message).
In case of a valid answer, the function code is returned. In the event of an error, a function
code assigned to the request is returned.
Error causes can be invalid CRC checksums, non-supported function codes or impermissible
data accesses.
Elements of the ADU:
MBAP (7 bytes)
•
Number of the bytes still to follow in the message.
•
Address of the inverter
•
The other bytes of the header are not described here.
•
Function code
•
The function codes exclusively refer to "4X registers", i. e. registers from the address
•
4000.
All data in the inverter can only be accessed via these 4X registers, see
•
.
^ 360
The 4xxxx reference is implicit, i. e. given by the function code used. In the frame there-
•
fore the leading 4 is omitted in the addressing process.
Lenze supports the basic 1 addressing of Modbus, i.e. the numbering of the registers
•
starts with 1 whereas addressing starts with 0. For example, the address 0 is used in
the frame when register 40001 is read.
Data or error code
•
Checksum
•
All ADU contents are represented in the Big Endian format (most significant byte first).
Function codes
Function code
0x03
0x06
0x10
0x17
Function code
3 0x03
6 0x06
16 0x10
23 0x17
Number of the Slave address
bytes still to fol-
low
2 bytes
1 byte
Basic settings .
^ 349
Function code in the event of an
error
0x83
0x86
0x90
0x97
Function name
Read Holding Registers
Preset Single Register
Preset Multiple Registers
Read/Write 4X Registers
Configuring the network
Protocol Data Unit (PDU)
Function code Data / error code
1 byte n byte
Data mapping
Supported error codes
0x01, 0x02, 0x03, 0x04
0x01, 0x02, 0x03, 0x04
0x01, 0x02, 0x03, 0x04
0x01, 0x02, 0x03, 0x04
Info
Reading of a single register or a group of several interconnected regis-
ters.
Writing of a single register.
Writing of a single register or a group of several interconnected registers.
Reading and writing within a transaction:
• Writing of a data block into a group of several interconnected regis-
ters.
• Reading from a block of interconnected registers.
Modbus TCP
Function codes
CRC
Checksum
2 bytes
355